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Geophysical monitoring of groundwater and soils pollution in the industrial area of Portovesme (sout-western Sardinia, Italy)
by
Manuela Barbieri
Dipartimento di Ingegneria del Territorio- Università di Cagliari-Italy
Coauthors: Giulio BARBIERI (1), Albert CASAS (2), Gaetano RANIERI (1). (1) Dipartimento di Ingegneria del Territorio- Università di Cagliari-Italy (2) Departamento de Geoquimica y Petrologia- Universidad de Barcelona- Spain
The study has been carried out in the coastal plain of Portovesme Industrial Area, south of the built-up areas of Portoscuso (Sardinia, Italy), where the aquifers laying in the quaternary sand deposits over the miocenic vulcanites are polluted in different ways by the waste landfills, the discharge liquors and the losses of liquids of the industries that work there since the first ’70 years. The study area mainly involves the soils and the aquifers under the plants of a society that extracts alumina from the bauxite through the Bayer process.
In the first phase of the study the present condition of the shallow aquifers have been verified by means of groundwater levels, pH and electric conductivity measurements in a monitoring net concerning the whole area of interest. The high pH and conductivity values pointed out wide and intense pollution phenomena both in the phreatic and in the underlying confined aquifer, up to the impervious bed of the vulcanites. Afterwards a set of Frequency Domain electromagnetic sounding (FEM-34) have been carried out throughout the whole study area; some Time Domain electromagnetic sounding (TEM-FAST) and electric resistivity and induced polarisation tomographies have been executed where the former geophysical prospecting showed the most significant anomalies. The results, compared also with the hydrogeological ones, have pointed out that the selected geophysical methods are suitable to identify soils and groundwater pollution phenomena, even with the presence of intense electromagnetic noise. In particular, the electromagnetic soundings have been useful to reconstruct the state of the contamination of the aquifers at different depths, while the electric tomographies have been detected the degradation of the soils.
Date received: October 2, 2004
Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caon-68.